combines ranges assuming a sorted array by start position

banding.c

#include <stdio.h>
#include <stdlib.h>


typedef struct {
    int start;
    int end;
} range_t;


range_t* band(range_t* ranges, int num_ranges) {
    range_t* bands = NULL;
    range_t* bands_ptr = NULL;
    range_t* cur = ranges;
    int start = -1;
    int  end = -1;
    int make_band = 0;
    int make_band = 0;
    int counter = 0;
    //init bands
    bands = (range_t*)malloc(num_ranges * sizeof(range_t));
    bands_ptr = bands;
    bands_ptr++;
    while (counter < num_ranges) {
        if (start == -1) {
            start = cur->start;
            end = cur->end;.

        }
        else if ( (cur->start < start) && (cur->end > start) ) {
            start = cur->start;
            if (cur->end > end) {
                end = cur->end;
            }
            make_band = 0;
        }
        else if ( (cur->end > end ) && ( cur->start < end ) ) {
            end = cur->end;
            if (cur->start < start) {
                start = cur->start;
            }
            make_band = 0;
        }
        else if( ( cur->start > start ) && ( cur->end < end ) ) {
            make_band = 0;
        }
        else {
            make_band = 1;
        }
        if (make_band) {
            bands_ptr->start = start;
            bands_ptr->end = end;
            bands_ptr++;//advance pointer
            //reset start and end
            start = cur->start;
            end = cur->end;
        }
        cur++;
        counter++;

    }
    return bands;


}

void print_ranges(range_t* ranges) {
    range_t* blah = ranges;
    int i = 0;
    for(i = 0; i < 7; i++, blah++) {
        printf("range start:%d end:%d\n", blah->start, blah->end);
    }
}

range_t* make_ranges() {
    range_t* ranges = (range_t*)malloc(7 * sizeof(range_t));
    ranges[0].start = 0;
    ranges[0].end = 50;
    ranges[1].start = 15;
    ranges[1].end = 75;
    ranges[2].start = 100;
    ranges[2].end = 300;
    ranges[3].start = 125;
    ranges[3].end = 250;
    ranges[4].start = 175;
    ranges[4].end = 200;
    ranges[5].start = 325;
    ranges[5].end = 400;
    ranges[6].start = 330;
    ranges[6].end = 400;
    print_ranges(ranges);
    return ranges;
}
int main(int argc, char* argv[]) {
    range_t* ranges = NULL;
    range_t*  bands = NULL;
    range_t* cur = NULL;
    int i = 0;
    ranges = make_ranges();
    bands = band(ranges, 7);
    cur = bands;
    while(i < 7) {
        if (cur){
            printf("%d start: %d end: %d\n", i, cur->start, cur->end);
        }
        cur++;
        i++;
    }
    return 0;
}